Energy Systems Flashcards
What is metabolism?
Sum of all processes going on in the body’s cells sustaining life
What is a nutrient?
sustain life, are needed to survive
What is a macro-nutrient?
nutrient consumed in large quantities: carbohydrates, proteins, fats, alcohol
What is metabolic regulation?
how foods are channelled and how they are later use
What is anabolic regulation?
making macro-nutrients from vitamins and small particles
What is catabolic regulation?
breaking down macro-nutrients into energy for use
What is the composition of ATP?
Adenosine + 3 phosphates linked together by very high energy phosphate bonds; ATPase breaks down these bonds and energy is released
How does the ATP-PCr system work?
- ATP broken down into ADP
- Phosphocreatine (creatine + phosphate) linked by high energy phosphate bond
- Creatine Kinase enzyme breaks down this bond and energy is released
- Loose phosphate molecule is used to resynthesise ATP
What is the cause of fatigue of the ATP-PCr system?
A depletion of PCr: the rate of demand is greater than rate of replenishment
How quickly does PCr depletion occur?
Within 3 to 15 seconds of an all out sprint
How quickly is PCr fully replenished?
Within a few minutes after a sprint
What is glycolysis?
Glycolysis is the process of converting glucose into pyruvate
What are the anaerobic energy systems?
the ATP-PCr system
the Lactic Acid system
they both function without oxygen
What is the second energy system used?
The Lactic Acid system or anaerobic glycolysis
How does the Lactic Acid system work?
Occurs when muscle are working above their lactate threshold
Glycogen is broken down and releases energy to resynthesize ATP
Enzyme: phosphorylase
By-product: Pyruvic Acid, converted into lactic acid due to absence of oxygen
When does Lactic Acid system start and how long does it last?
During high intensity exercise, takes about 10secs to kick it and lasts for another 20secs; good for stop/start games , field and court sports
What is the third energy system used?
Aerobic Glycolysis (requires oxygen)
When does Aerobic glycolysis work?
After 30secs of intensive physical activity for up to 2 hours, aerobic system becomes main source of energy
What are the benefits of the ATP-PCr system?
- Stored in the muscle so it is readily available
- Does not require oxygen
- Very simple reaction so can happen quickly
- No negative by-products
What are the disadvantages of the ATP-PCr system?
Very quickly depleted so it is useful for short explosive exercise (e.g. javelin throw) but not for longer than 10secs
What are the 3 benefits of the Lactic Acid System?
- Does not require oxygen
- Produces a lot more ATP than ATP-PCr system
- Lasts up to a few minutes
What are the 2 disadvantages of the Lactic Acid System?
- Lasts no more than a few minutes, requires another system for longer exercise
- Lactate builds up in the blood which increases muscle acidity and causes fatigue
What are the 4 benefits of the Aerobic System?
- Can produce energy for a very long time
- Can use fat as a fuel and spare glycogen (provided there is enough oxygen available)
- Abundant energy produced compared to anaerobic systems
- No harmful waste products
What is the disadvantage of the Aerobic System?
Slow to get going due to complicated process
What is the metabolism for glycerol?
Aerobic Glycolysis; requires oxygen
Fuel: glycerol
Produces Acetyl CoA through phosphoglyceraldehyde and begins the Citric Acid Cycle
What are the 3 causes of fatigue of the oxidative system (aerobic glycolysis and lypolysis)?
- Muscle glycogen depletion
- Liver glycogen depletion
- Hypoglycaemia
What is the metabolism for glycerol?
Aerobic Glycolysis (fat)
What is the role of ATPase?
ATPase breaks down high energy phosphate bonds of ATP to release energy
What is ATP?
Fuel of daily activity
How many cal/mol is ATP?
12 cal/mol
How heavy is ATP? (g/mol)
551g/mol
How does the Lactic Acid system work?
Uses glucose (bloodstream) or glycogen (muscle or liver) as fuel and does not require oxygen
How long does is take to replenish glycogen stores after aerobic glycolysis fatigue?
Takes 24-48hours to replenish glycogen
How does aerobic glycolysis (CHO) work?
Fuelled by glycogen
Regulated by the enzyme PFK
Produces Pyruvic Acid which becomes Acetyl-CoA at the mitochondria
When does the Citric Acid Cycle begin?
After oxidative system produces Acetyl CoA
How does beta-Oxidation work?
Fuelled by NEFA (non-esterified fatty acids)
Produces Acetic Acid then Acetyl CoA
Begins the Citric Acid Cycle
What is the metabolism for fatty acids?
beta Oxidation (aerobic: requires oxygen)
How does aerobic glycolysis (fat) work?
Fuelled by glycerol
Produces phosphorusglyceraldehyde then Acetyl CoA
Begins the Citric Acid Cycle
What can PCr recovery measurements be useful index for? (2 answers)
- Relative muscle oxidative capacity
- Mitochondrial content in the muscle
(Haseler et al. 1999)
What is the recovery of PCr limited by?
O2 supply
Haseler et al. 1999
